U.S. patent number 5,322,630 [Application Number 07/962,494] was granted by the patent office on 1994-06-21 for amine derivatives as corrosion inhibitors.
This patent grant is currently assigned to Exxon Chemical Patents Inc.. Invention is credited to Brent I. Bourland, Niall Carruthers, Paul J. Clewlow, John A. Haslegrave, James R. Looney, Terence M. O'Brien, Daniel S. Sullivan, Dennis A. Williams.
United States Patent |
5,322,630 |
Williams , et al. |
June 21, 1994 |
Amine derivatives as corrosion inhibitors
Abstract
A method of acidizing a subterranean formation with an acqueous
acid solution wherein the acid solution contains corrosion
inhibiting amounts of an amine derivative prepared by reacting an
unsaturated carboxylic acid with (a) fatty amine or polyamine, or
(b) a fatty amido amine or polyamine, or (c) a fatty imidazoline
amine or polyamine. The derivative is characterized by the absence
of primary amino groups, and preferably contains only tertiary
amino groups.
Inventors: |
Williams; Dennis A. (Houston,
TX), Looney; James R. (Houston, TX), Sullivan; Daniel
S. (Houston, TX), Bourland; Brent I. (Kingwood, TX),
Haslegrave; John A. (Abingdon, GB2), Clewlow; Paul
J. (Faringdon, GB2), Carruthers; Niall (Abingdon,
GB2), O'Brien; Terence M. (New Hinksey,
GB2) |
Assignee: |
Exxon Chemical Patents Inc.
(Linden, NJ)
|
Family
ID: |
25505950 |
Appl.
No.: |
07/962,494 |
Filed: |
October 15, 1992 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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882833 |
May 14, 1992 |
|
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882848 |
May 14, 1992 |
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Current U.S.
Class: |
507/241; 166/312;
166/300; 166/307; 507/243; 507/244; 507/939 |
Current CPC
Class: |
C09K
8/54 (20130101); C23F 11/04 (20130101); C09K
8/74 (20130101); Y10S 507/939 (20130101) |
Current International
Class: |
C09K
8/60 (20060101); C09K 8/54 (20060101); C09K
8/74 (20060101); C23F 11/04 (20060101); E21B
043/27 () |
Field of
Search: |
;252/8.553,8.555,392,394
;422/16 ;208/47 ;166/300,307,312 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Stoll; Robert L.
Assistant Examiner: Fee; Valerie
Attorney, Agent or Firm: Graham; R. L.
Parent Case Text
RELATED APPLICATIONS
This is a continuation-in-part of U.S. patent application Ser. No.
882,833, filed May 14, 1992 now pending and U.S. patent application
Ser. No. 882,848, filed May 14, 1992 now pending.
Claims
What is claimed is:
1. A method of acidizing a subterranean formation penetrated by a
borehole which has metal pipe positioned therein wherein an aqueous
acid solution is pumped down said pipe and into the formation, the
improvement comprising introducing a corrosion inhibitor into the
aqueous acid solution at a concentration to inhibit corrosion of
the metal, said corrosion inhibitor comprising a compound of the
following formula: ##STR17## where R is a C.sub.6-20
hydrocarbon;
Y is one of the following:
(a) --NR.sub.1 -- where n is 1, 2, or 3;
(b) --CO--NH-- where n is an integer 1-6;
(c) ##STR18## in which X is an alkylene group of 2 to 6 carbon
atoms and n is an integer of 1 to 6;
R.sub.1 is independently H, or
or a C.sub.6-20 hydrocarbon or
a C.sub.6-20 hydrocarbon carbonyl; and
R.sub.2 is H, or COOH or C.sub.6-20 hydrocarbon-carbonyl or a
C.sub.6 -C-.sub.20 hydrocarbon
wherein the compound contains at least one --(CH.sub.2).sub.1-4
COOH group or salt thereof and no primary amino groups.
2. The method of claim 1 in which each amino group in the compound
is tertiary.
3. The method of claim 1 in which in the amine R is the hydrocarbon
residue of a naturally occurring fatty acid.
4. The method of claim 1 wherein the amine corrosion inhibitor has
the formula: ##STR19## or a salt thereof.
5. The method of claim 1 wherein Y is ##STR20## where X is an
alkylene group of 2 to 6 carbon atoms and n is 1 to 6.
6. The method of claim 1 wherein Y is an amide and --CO--N-- and n
is an integer of 1-6.
7. The method of claim 1 wherein the compound is of the formula
(III): ##STR21## where each R.sub.1 is H or --(CH.sub.2).sub.2
COOH; or salt thereof.
8. A method of acidizing a subterranean formation penetrated by a
borehole which has metal pipe positioned therein wherein an aqueous
acid solution is pumped down said pipe and into the formation, the
improvement comprising introducing a corrosion inhibitor into the
aqueous acid solution at a concentration to inhibit corrosion of
the metal, said corrosion inhibitor comprising a compound of the
following formula: ##STR22## where R is a C.sub.6-20
hydrocarbon;
n is 1, 2, or 3;
R.sub.1 is independently H, or --(CH.sub.2).sub.1-4 COOH or a
C.sub.6-20 hydrocarbon; where the compound contains at least one
group or salt thereof and no primary amines.
9. The method of claim 8 wherein n is 1 and R is a residue of an
acid found in coconut oil and tallow oil.
10. The method of claim 8 wherein the corrosion inhibitor is the
reaction product of a coco or tallow diaminopropane with acrylic
acid.
11. In a method of acidizing a subterranean formation penetrated by
a borehole which has metal pipe positioned therein wherein an
aqueous acid solution is pumped down said pipe and into the
formation, the improvement comprising introducing a corrosion
inhibitor into the aqueous acid solution at a concentration to
inhibit corrosion of the metal, said corrosion inhibitor comprising
a compound which is the reaction product of a condensation reaction
between a C.sub.2 -C.sub.6 alkyl di- or polyamine and a C-.sub.6-20
fatty acid, subsequently reacted with a C.sub.3 -C.sub.5
unsaturated carboxylic acid or halocarboxylic acid, wherein the
reaction product contains no primary amino groups.
12. An inhibited well treating fluid for acidizing subterranean
formations which comprises:
(a) an aqueous acid solution;
(b) inhibiting amounts of a corrosion inhibitor dissolved or
dispersed in said aqueous acid solution, said corrosion inhibitor
having the following formula: ##STR23## where R is a C.sub.6-20
hydrocarbon;
Y is one of the following:
(1) --NR.sub.1 -- where n is 1, 2, or 3;
(2) --CO--NH-- where n is an integer 1-6;
(3) ##STR24## in which X is an alkylene group of 2 to 6 carbon
atoms and n is an integer of 1 to 6;
R.sub.1 is independently H, or (CH.sub.2).sub.1-4 COOH or a
C.sub.6-20 hydrocarbon, or
a C.sub.6-20 hydrocarbon carbonyl; and
R.sub.2 is H, or CH.sub.2 .sub.1-4 COOH, or a hydrocarbon, or
C.sub.6-20 hydrocarbon-carbonyl, the compound containing at least
one --(CH.sub.2).sub.1-4 COOH; group or salt thereof and no primary
amino groups.
13. A method of acidizing a subterranean formation penetrated by a
borehole which has metal pipe positioned therein wherein an aqueous
acid solution is pumped down said pipe and into the formation, the
improvement comprising introducing a corrosion inhibitor into the
aqueous acid solution at a concentration to inhibit corrosion of
the metal, said corrosion inhibitor comprising reaction product of
(a) a C.sub.6 -C.sub.20 alkyl C.sub.2 -C.sub.6 alkylene polyamine
containing from 2 to 4 N atoms having at least one reactive H and
(b) an unsaturated C.sub.3 -C.sub.5 carboxylic acid to form a
substituted poly-amine having no primary amino groups.
14. The method of claim 13 wherein the amount of carboxylic acid is
sufficient to produce a substituted amine with all tertiary amino
groups.
15. A method of acidizing a subterranean formation penetrated by a
borehole which has metal pipe positioned therein wherein an aqueous
acid solution is pumped down said pipe and into the formation, the
improvement comprising introducing a corrosion inhibitor into the
aqueous acid solution at a concentration to inhibit corrosion of
the metal, said corrosion inhibitor comprising a compound prepared
by reacting a fatty acid with a C.sub.2 -C.sub.6 alkylene polyamine
having from 2 to 6N atoms to form an amino amide, and subsequently
reacting the amide with a C.sub.3 -C.sub.5 unsaturated carboxylic
acid to form a compound having no primary amino groups.
16. The method of claim 15 wherein reaction of the fatty acid and
the polyamine produces a heterocyclic compound containing a C.sub.2
-C.sub.6 alkylene group in the ring.
Description
BACKGROUND OF THE INVENTION
The present invention relates to the use of compounds and
compositions as corrosion inhibitors in situations where they may
come into contact with the natural environment e.g. by discharge of
produced water, and to a method of inhibiting corrosion using these
materials. In one preferred aspect, the present invention relates
to the use of a nontoxic corrosion inhibitor in oil field acidizing
operations.
In order to preserve metals, and particularly ferrous metals, in
contact with corrosive liquids in gas and oil field applications,
corrosion inhibitors are added to many systems, e.g. cooling
systems, refinery units, pipelines, steam generators, oil
production units, and oil field treating fluids. A variety of
corrosion inhibitors are known. For example, GA-B-2009133 describes
the use of a composition which comprises an amine-carboxylic acid
such as dodecylamine propionic acid, and a nitrogen-containing
compound containing an organic hydrophobic group, such as
N-(3-octoxypropyl)-propylenediamine.
EP-A-256802 describes a method of inhibiting corrosion of metal
surfaces in contact with a corrosive hydrocarbon-containing medium
comprising contacting the metal surfaces with the reaction product
of (a) tallow triamine or tallow tetramine and (b) an acrylic acid
type compound, in which the ratio of the two reagents is preferably
1:1.
Although corrosion inhibitors of many types are known, the
materials which have been found most effective in practice have the
disadvantage of toxicity to the environment. Toxicity to the marine
or freshwater environment is of particular concern. In gas and oil
field applications, much work is done off-shore or on the coast. If
a corrosion inhibitor enters the sea or a stretch of fresh water,
on land or in lakes or streams, even at relatively low
concentrations, the corrosion inhibitor can kill microorganisms,
causing an imbalance in the environment. Attempts have therefore
been made to identify materials which are successful corrosion
inhibitors but at the same time are less toxic to the environment
than known inhibitors. The applicants have found that adducts of a
fatty amine and an unsaturated acid in which the product contains
no primary amino groups, and only secondary or tertiary, more
preferably tertiary, amine groups has a lower toxicity to the
environment (referred to as ecotoxicity).
SUMMARY OF THE INVENTION
The present invention therefore provides use as a corrosion
inhibitor in a marine or freshwater environment of an amine which
is a compound of the formula I: ##STR1## where R is a C.sub.6-20
hydrocarbon;
Y is one of the following:
(a) --NR.sub.1 -- where n is 1, 2, or 3;
(b) --CO--NH-- where n is an integer 1-6;
(c) ##STR2## in which X is an alkylene group of 2 to 6 carbon atoms
and n is an integer of 1 to 6;
R.sub.1 is independently H, or --[(CH.sub.2).sub.1-4 ] COOH
or a C.sub.6-20 hydrocarbon, or
a C.sub.6-20 hydrocarbon carbonyl;
R.sub.2 is H, or [(CH.sub.2).sub.1-4 ]COOH or a C-.sub.6-20
hydrocarbon C.sub.6-20 hydrocarbonyl, where R.sub.1 is the same or
different from R.sub.2,
wherein the compound contains at least one (CH.sub.2).sub.1-4 COOH
group or salt thereof and no primary amines.
As used herein, the term C.sub.6-20 hydrocarbon carbonyl means a
group having the following formula: ##STR3## where R.sub.3 is a
C.sub.5 -C.sub.19 hydrocarbon.
The inhibitor of Formula I is prepared by (a) reacting a fatty
amine with a unsaturated carboxylic acid or (b) reacting a fatty
acid with an amine to form an amide or imidazoline and then
reacting this product with an unsaturated carboxylic acid. The
final compound contains no primary amines. (For convenience, this
is also referred to as no primary amino groups.)
The present invention also provides a method of inhibiting
corrosion of a metal by a liquid system in, at or near, marine or
freshwater environment which comprises providing in the liquid an
amine as defined above.
It has been found that the amines defined above have favorable
ecotoxicity levels in marine or freshwater environments. The
ecotoxicity decreases with increasing substitutions on the N atoms
present i.e. it appears that tertiary groups are less toxic than
secondary groups which are in turn less toxic than primary groups.
Preferably, therefore, each amine group is secondary or tertiary,
more preferably tertiary.
Use in a marine or freshwater environment is intended to mean use
in an environment in which the corrosion inhibitor in normal usage
may come into contact with an area of seawater or fresh water or
land.
A particular advantageous us of the low toxicity corrosion
inhibitor of the present invention is in oil field acidizing
operations used in the stimulation of subterranean formations. Such
operations include hydraulic fracturing and matrix acidizing. In
oil field acidizing, an acid solution is pumped through the well
tubulars and injected into the formation where the acid reacts with
formation material, increasing the permeability of the formation
and/or reducing formation damage. Because of the corrosivity of the
acid, corrosion inhibitors are required in the acid solution to
protect the tubulars and other metals which the acid solution
contacts. Following the acidizing operation, the spent acid, which
itself may no longer be toxic, must be disposed of because of
environmental concerns. It is increasingly important that the
corrosion inhibitor be nontoxic or of low toxicity, since the spent
acid may be disposed of in marine or fresh water environments.
DESCRIPTIONS OF THE PREFERRED EMBODIMENTS
As mentioned above, the method of the present invention involves
the use of a low toxicity corrosion inhibitor in aqueous oil field
liquids. The corrosion inhibitors are environmentally safe for
disposal or in the case of spills of liquids containing them, the
corrosion inhibitor useful in the present invention is an amine
derivative having the general formula (I) indicated above. In
preferred embodiments, the corrosion inhibitor will have two
general forms: Formula IA and IB described below.
FORMULA IA
The corrosion inhibitor of FORMULA IA where Y is --NR.sub.1 -- and
R.sub.2 =R.sub.1 may be represented as follows: ##STR4## where R
and n are the same as described in FORMULA IA, and R.sub.1 is H,
--[(CH.sub.2).sub.1-4 ] COOH, or C.sub.6-20 hydrocarbon wherein the
compound contains at least one (CH.sub.2).sub.1-4 COOH or salt
thereof and no primary amines.
The hydrocarbon group or groups of from 6 to 20 carbon atoms of
FORMULA IA and IB may be straight or branched, saturated or
unsaturated, and may be aliphatic or may contain one or more
aromatic groups. Preferably the hydrocarbon group is straight chain
aliphatic and is saturated, optionally with up to 20% of the chains
being unsaturated. Preferably the hydrocarbon contains 12 to 20
carbon atoms, more preferably 16 to 20 carbon atoms. It is
preferred that R is the hydrocarbon residue of a naturally
occurring fatty acid, which is optionally hydrogenated e.g. the
residue of caproic, caprylic, capric, lauric, myristic, palmitic,
stearic, palmitoleic, oleic, linoleic or linolenic acid. The amines
used in the present invention can conveniently be formed by the
reaction of a fatty amine and an unsaturated acid in which case R
corresponds to the fatty part of the amine. Fatty amines are
readily available in which the fatty portion is a mixture of
hydrocarbon groups. For example, the amine, diamine or triamine of
hydrocarbon residues of coconut oil or tallow oil are readily
available.
When R.sub.1 of FORMULA IA is a hydrocarbon it may be the residue
of a naturally occurring fatty acid as described above for R, or it
may be an artificially synthesized hydrocarbon. If R.sub.1 is a
hydrocarbon, it is preferably a residue of a naturally occurring
fatty acid.
However, R.sub.1 is preferably H or --[(CH.sub.2).sub.1-4 ]COOH,
and most preferably --[(CH.sub.2).sub.1-4 ]COOH. The alkyl group
may be straight chain or branched. Conveniently the compound of
FORMULA IA is produced by adding acrylic acid to a fatty amine,
which results in a compound in which R.sub.1 is --CH.sub.2 CH.sub.2
COOH.
The C.sub.2-6 alkyl group linking the fatty hydrocarbon and amino
groups in the compound of FORMULA IA may be straight or branched.
Conveniently it is a propylene or hexylene group since the starting
amines are either available commercially or can be readily
synthesized. The amine of FORMULA IA may contain 1, 2, 3 or 4 amino
groups. It is preferred for it to contain 2 amino groups since the
tests carried out so far suggest that such compounds provide the
optimum in terms of ease of production and handling, good corrosion
inhibition properties and low ecotoxicity. Diamine compounds
correspond to compounds of the FORMULA IA in which n is 1.
The amine may be present in the form of a salt, for example an
alkali metal salt such as sodium or potassium, an alkaline earth
metal salt such as magnesium or calcium, or an ammonium salt.
Preferred amines of FORMULA IA include those of FORMULA IIA:
##STR5## in which tallow indicates the residue of an acid found in
beef tallow, and each R.sub.1 is independently (a) H or (b)
--(C.sub.2-4 alkyl)COOH and salts thereof. Preferably R.sub.1 is
--[(CH.sub.2).sub.1-4 ]COOH, conveniently CH.sub.2 CH.sub.2 COOH.
Thus a particularly preferred compound is of FORMULA IIIA:
##STR6##
Compounds of the FORMULA IA in which R.sub.1 is H, a C.sub.6-20
hydrocarbon or --[(CH.sub.2).sub.2-4 ]COOH may conveniently be
produced by reacting an amine of the FORMULA IVA ##STR7## where R
and n are as defined above and R.sub.1 is H or a C.sub.6-20
hydrocarbon, with an acid of FORMULA VA
in which m is 0, 1 or 2, each R' is hydrogen or when m is 1, R' may
be methyl, and Z is OH or alkyl. To produce a compound in which
R.sub.1 is H, a C.sub.6-20 hydrocarbon, or --[(CH.sub.2).sub.1-4
]COOH, the amine of FORMULA IVA may be reacted with a chloro acid
of FORMULA VIA
The molar ratio of acid of FORMULA VA or VIA to amine of FORMULA
IVA should be chosen to ensure the desired level of substitution
takes place. Typically therefore to avoid the presence of primary
amine groups the molar ratio will be at least 2:1, more preferably
3:1 when the starting amine contains two amino groups, at least
3:1, more preferably 4:1 when the starting amine is a triamine and
so on. A slight molar excess (e.g. about 10%) of acid is generally
used, e.g. for a diamine the acid may be used in a molar ratio of
about 3.3:1.
Preferably the compounds of FORMULA IA are made by reacting the
compounds of FORMULA IVA and VA since if the chloro acid is used as
a starting material, it is generally difficult to remove all the
chlorine-containing material from the product, and
chlorine-containing compounds can damage the environment.
Preferably the acid is acrylic acid.
The reaction of acrylic acid with the primary amine yields
predominantly the B-amine propionic acid derivative directly.
Depending on the distance between the amino group and the acid
group, the product may be a cyclic internal salt.
The reaction may be carried out by heating a solution of the amine
in a suitable solvent, conveniently an alcohol such as isobutanol
or isopropanol or water. The required quantity of the acid is
gradually introduced. The temperature at which the reaction is
carried out is generally from 50.degree. C. up to the reflux
temperature of the reaction mixture, typically 60.degree. to
100.degree. C.
The compounds tend not to be soluble in water or brine, but are
dispersible to some extent in water.
FORMULA IB
The corrosion inhibitor of FORMULA IB may be represented as
follows: ##STR8##
Y' is the group represented in (b) and (c) of FORMULA I; and where
n, R, R.sub.1, and R.sub.2 are described in FORMULA I and wherein
the compound contains at least one (CH.sub.2).sub.1-4 COOH group
and no primary amines. R.sub.2 is preferably H, or the carboxylic
acid group, or the carbonyl group.
The amine derivative (Y') may contain a heterocyclic group of the
formula ##STR9##
In this formula X may be an alkylene group of 2 to 6 carbon atoms
e.g. ethylene or propylene. When X is ethylene, the heterocyclic
group is imidazoline. X may be straight chain or may be branched,
such that the heterocyclic ring is substituted by an alkyl of up to
4 carbon atoms.
The derivative of FORMULA IB may contain one or more amido
groups.
R.sub.1 in the derivative of FORMULA IB is preferably H or a
carboxylic acid group of 2 to 5 carbon atoms. Tests currently
appear to indicate tertiary groups are less toxic than secondary
amino groups, which are in turn less toxic than primary amino
groups. If a heterocyclic ring is present the nitrogen atoms in the
ring are considered tertiary. In view of the favorable results
shown for N-- substitution it is preferred that each R.sub.1 is a
carboxylic acid group. Conveniently, R.sub.1 is derived from
acrylic acid, in which case R.sub.1 in FORMULA IB is --CH.sub.2
CH.sub.2 COOH. R.sub.2 is similarly conveniently derived from
acrylic acid and is therefore preferably --CH.sub.2 CH.sub.2 COOH
or H.
The derivative may optionally contain 1 or more alkyl amino groups
between the group Y and the group R.sub.2. Each amino group may be
optionally substituted by an acid group or a C.sub.6-20 hydrocarbon
or C.sub.6 -C.sub.20 hydrocarbon-carbonyl. Preferably the
derivative contains 2 or 3 amino groups i.e. n is 2 or 3.
The C.sub.2-6 alkyl group linking the group Y.sup.1 and each amino
group may be a straight or branched alkyl group. Conveniently, it
is an ethylene, propylene or hexylene group since the starting
amines to produce such compounds are either available commercially
or can be readily synthesized.
The derivative may be present in the form of a salt, for example an
alkali metal salt such as sodium or potassium, an alkaline earth
metal salt such as magnesium or calcium, or an ammonium salt.
Particularly preferred derivatives are those of FORMULA (IIB).
##STR10## where each R.sub.1 is H or (CH.sub.2).sub.2 COOH.
Compounds of the FORMULA IB may conveniently be produced by
reacting an amine or a heterocyclic compound with an unsaturated
acid. This may be represented as reacting compound of the FORMULA
(IIIB): ##STR11## in which R, Y' and n are as defined above and
each R.sub.1 ' is independently H, C.sub.6-20 hydrocarbon, or
C.sub.6-20 hydrocarbon-carbonyl with an acid of the FORMULA
(IVB):
in which m is 0, 1 or 2, each R' is hydrogen or, when m is 1, R'
may be methyl, and Z is OH or alkoxy. If Z is alkoxy the product is
hydrolysed to produce the corresponding acid.
The salt, if desired, may e formed using processes known in the
art.
The amine derivatives may also be produced by reacting a compound
of the FORMULA IIIB as defined above with an acid of the FORMULA
VB:
where Q is halogen, preferably chloro, and optionally forming a
salt thereof.
The molar ratio of acid of FORMULA IVB or VB to compound of FORMULA
IIIB should be chosen to ensure that the desired level of
N-substitution takes place. N-atoms which are part of an amide
group will not react with the acid but any other --NH-- groups will
react. Typically, therefore, to avoid the presence of primary amino
groups the molar ratio will be at least 1:1 when n is 1 in the
starting compound, more preferably 2:1 when n is 1 and R'.sub.1 is
H. A slight molar excess (e.g. about 10%) of acid is generally
used, e.g. for n=1 and R.sub.1 '=H, the acid is preferably used in
a molar ratio of about 2.2:1.
Preferably the compounds of FORMULA IB are made by reacting the
compounds of FORMULA IIIB and IVB since if the chloro acid is used
as a starting material it is generally difficult to remove all the
chlorine-containing material from the product, and
chlorine-containing compounds can damage the environment.
Preferably, the compound of FORMULA IVB is acrylic acid.
The reaction of compounds of FORMULA IIIB and IVB or VB may be
undertaken by dissolving the compound of FORMULA IIB in a
convenient solvent, e.g. secondary butanol, adding the acid and
heating the mixture until the reaction is complete. The reaction
may be carried out at temperatures of from room temperature up to
the reflux temperature of the reaction mixture, typically
60.degree. C. to 120.degree. C.
The starting compounds of FORMULA IIIB may be synthesized by
reacting a fatty acid with an alkyl amine. Suitable fatty acids are
those indicated on page 3, with respect to the derivation of R. In
particular, tall oil fatty acid (TOFA) and oleic acid are suitable
starting materials. The acid and amine initially react to produce
an amide i.e. a compound of the FORMULA IIIB in which Y is
--CO--NH--. Dehydrolysis of the amide results in cyclisation to
give a compound of the FORMULA IIIB in which Y is a heterocyclic
ring. An incomplete cyclisation reaction results in a mixture of
compounds of FORMULA IIIB in which Y is an amide group and those in
which Y is a heterocyclic ring. Some starting material and some
mono-, di- or polyamides may also be present, depending on the
starting amine in the system. This mixture may be used to produce a
successful corrosion inhibitor.
The alkyl amine is chosen to give the appropriate heterocyclic ring
and/or amide group(s) and, if desire, alkyl amine group attached to
the heterocyclic ring or amide. Suitable alkyl amines include e.g.
ethylene diamine, diethylenetriamine (DETA), triethylenetetramine
(TETA) and tetraethylenepentamine (TEPA).
The reaction of the fatty acid and an alkyl amine may be carried
out by heating the reactants in a suitable solvent e.g. an aromatic
hydrocarbon. The reaction may be carried out initially at the
reflux temperature of the mixture, e.g. 140.degree. C. to
180.degree. C., and the temperature ma be increased to e.g.
200.degree. to 230.degree. C. to form the heterocyclic ring.
OPERATION
As mentioned above, the method of the present invention employs an
amine corrosion inhibitor of FORMULA I in the acidizing of
subterranean formations. Any of the known oil field acids may be
used. These are referred to herein as "well treating acids" and
include aqueous solutions of hydrochloric acid (HCl), hydrofluoric
acid (HF), mixtures of HCl and HF (i.e. mud acid), acetic acid,
formic acid, and other organic acids and anhydrides. The most
common acids are 3% HCl, 71/2% HCl, 15% HCl, 28% HCl and blends of
HCl and HF (mud acid). Mud acid is normally a blend of 6 to 12% of
HCl and 11/2 to 6% HF.
The amine derivative of FORMULA I may be added to the acid solution
in the form of a solution or dispersion in water and/or an organic
solvent. Examples of suitable solvents are alcohols such as
methanol, ethanol, isopropanol, isobutanol, secondary butanol,
glycols and aliphatic and aromatic hydrocarbons. The solubility of
the compounds in water can be improved by forming a salt e.g. a
sodium, potassium, magnesium or ammonium salt.
The amount of active ingredient in the acid solution to achieve
sufficient corrosion protection varies with the system in which the
inhibitor is being used. Methods for monitoring the severity of
corrosion in different systems are well known, and may be used to
decide the effective amount of active ingredient required in a
particular situation.
In general it is envisioned that the derivatives will be used in
amounts of up to 15,000 ppm, but typically within the range of 500
to 5,000 ppm based on the weight of the acid solution (e.g. 0.5 to
40 gal/1000 gal or 0.05-4.0% vol).
In the compositions the derivatives may be used in combination with
known corrosion inhibitors, although to achieve the low ecotoxicity
which is desirable, it is preferred that the composition contains
only corrosion inhibitors which have low ecotoxicity.
The compositions may contain other materials which it is known to
include in corrosion inhibiting compositions e.g. scale inhibitors
and/or surfactants. In some instances it may be desirable to
include a biocide in the composition.
EXAMPLES
The following examples illustrate the preparation of amine
derivatives useful in the present invention.
EXAMPLE 1
A solution of the appropriate starting amine in isopropyl alcohol
(50% based on the total amount of reactants to be used) was heated
to 60.degree. C. with stirring under nitrogen. The requisite
quantity of acrylic acid was then added dropwise. After addition
had been completed, the reaction temperature was raised to
85.degree. C. and maintained at this temperature for 10 hours.
Clear, pale yellow-colored solutions resulted.
Table A sets out the starting amines and amounts of acid used to
form the adducts.
TABLE A ______________________________________ MOLAR RATIO OF AMINE
TO EXAMPLE STARTING AMINE ACRYLIC ACID
______________________________________ 1
Coco-1,3-diaminopropane.sup.(a) 1:1.1 2 Coco-1,3-diaminopropane
1:2.2 3 Coco-1,3-diaminopropane 1:3.3 4
Tallow-1,3-diaminopropane.sup.(b) 1:1.1 5 Tallow-1,3-dimainopropane
1:2.2 6 Tallow-1,3-diaminopropane 1:3.3
______________________________________ .sup.(a) Sold as Duomeen C
by Akzo .sup.(b) Sold as Duomeen T by Akzo
EXAMPLE 2
(1) Preparation of imidazoline amine ##STR12##
Reactants
TOFA (tall oil fatty acid, C.sub.17 CO.sub.2 H)--238.4 g (0.8M)
DETA (diethylene triamine) (H.sub.2 NCH.sub.2 CH.sub.2).sub.2
NH--90.79 g (0.88M, 1.1 eq)
SOLVESSO 100 (aromatic hydrocarbons)--82 g
Method
To a stirring solution of TOFA (238.4 g) in Solvesso 100 (82 g) at
room temperature under N.sub.2 was added DETA (90.79 g). A slight
temperature rise was observed and also a slight color change (pale
yellow to pale orange). The stirring solution was then heated to
reflux (160.degree. C.).
After refluxing for about 11/2 hours approximately 15 ml of a milky
emulsion was obtained. The temperature was increased to 210.degree.
C. to remove the second mole of H.sub.2 O to form the required
imidazoline.
(2) Synthesis of TOFA/TETA Imidazoline Plus 3Eq. Acrylic Acid
Reagents
TOFA/ TETA IMIDAZOLINE (80% in solvesso 100) 145 g (0.25M)
ACRYLIC ACID 59.4 g (0.82M, 3.3 eq).
Secondary Butanol (SBA) 205 g
Method
A solution of TOFA/TETA imidazoline (145 g) in SBA (205 g) was
stirred at room temperature under N.sub.2. To this was carefully
added, dropwise, acrylic acid (59.4 g). A temperature rise from
26.degree. C. was observed.
After exotherms had ceased, the reaction temperature was raised to
reflux (about 100.degree. C.). The reaction was monitored to
completion using thin layer chromatography (TLC). (1:1
acetone/heptane, silica gel place, I.sub.2 development).
Formulation
Inhibitor A is representative of FORMULA IB and is an example of
chemistry described for Example 2 in the previous section.
Inhibitor A is a TOFA/TETA imidazoline reacted with 3.5 Eq. of
acrylic acid. It is 50% by weight active in sec-butyl alcohol
solvent. Inhibitor A has the following formula: ##STR13##
Inhibitor B is representative of FORMULA IA and is an example of
chemistry described for Example 1 in the previous section. It is
the reaction product of Tallow--1, 3, diaminopropane and 3.3 Eq. of
acrylic acid. It is then reacted with NaOH to form the mono-sodium
salt. It is 31.3% by weight active in a water/isopropanol solvent.
Inhibitor B has the following formula: ##STR14##
Inhibitor C is representative of FORMULA IB and is an example of
the chemistry described for Example 2 in the previous section.
Like Inhibitor A, it is 50% by weight active in sec-butyl alcohol.
However, it is the reaction product of a TOFA/TEPA imidazoline and
4.5 Eq. of acrylic acid. Inhibitor C has the following formula:
##STR15##
Inhibitor D is representative of FORMULA IB and is an example of
the chemistry described in section (i) of Example 2 in the previous
section. It is the 2:1 mole ration of TOFA/TEPA amide reacted with
5.0 Eq. of acrylic acid. It is 50% by weight active in sec-butyl
alcohol. Inhibitor D has the following formula: ##STR16##
Inhibitors A, B, C, and D were added to the acid formulation
without modification. In addition, at 200.degree. F. and higher the
known acid corrosion inhibitor extenders, formic acid or potassium
iodide, were evaluated with inhibitors A, B and C to see if
synergies existed.
Test Procedure
Each Inhibitor (A, B, C, or D) was added at the listed
concentration to an aqueous acid solution and mixed. Inhibitor
extender, if any, was added and mixed. A pre-weighed steel coupon
was placed in a bottle with 100 ml of the acid solution. The types
of steel tested included N-80 tubing steel, CR-13 tubing steel, and
CR-2205 tubing steel (API Specification Grade Duplex containing
21.9 wt. % chromium). All tests, at 200.degree. F. or lower
temperature, were carried out at atmospheric pressure for 6 hours
at test temperature. Those tests performed at a temperature of
225.degree. F. were performed at elevated pressure (2,000 psi) and
for a test time of 4 hours at temperature.
After exposure to the acid solution for the reported time, the
coupons were cleaned, dried, and weighed. The corrosion rate was
calculated from the weight loss and reported in Tables I, II, III,
and IV.
Table I gives the data measured at 125.degree. F. As can be seen,
addition of Inhibitors A, B, C, or D substantially reduces the rate
as compared with rates measured for coupons in acid with no
inhibitor. Especially notable are the results for CR-13 and CR-2205
in 15% HCl (Tests 16 through 33). These tests illustrate that as
little as 2 gallons of Inhibitor per 1,000 gallons of acid will
protect the steel. Of the four inhibitors, A and C appear to be the
best for this application.
Results of tests in 10% Formic acid are less dramatic because the
CR-13 and CR-2205 are less affected by this acid. However,
corrosion rates are dramatically reduced by addition of the
inhibitors. Results for tests with N-80 in both 10% Formic and 15%
HCl show the inhibitors are very effective in controlling
corrosion.
Table II contains results for tests conducted at 175.degree. F.
Excellent results were observed for all Inhibitors. Again it is
notable that excellent results were observed when the Inhibitors
were tested on CR-13 steel coupons.
The effect of corrosion inhibitor in 10% Formic Acid was more
easily measured at 175.degree. F. This is because the corrosion
rates are much higher and the corrosion inhibiting effect of
compounds A, B, C, and D were much more evident.
Table III lists results of testing at 200.degree. F. Tests with
Inhibitors A, B or C without extender show them to lower corrosion
rates as compared with a blank, but the rates are higher than
desired. When the inhibitors are used in conjunction with the known
acid corrosion inhibitor extender KI, the results are satisfactory.
Use of the extender Formic Acid did not show a similar effect.
Table IV lists the results of tests conducted at 225.degree. F.,
2000 psi pressure, and for a test time at 225.degree. F. of 4
hours. The combination of inhibitor and KI gave good protection to
N-80 and CR-13 steel in both 12/3 Mud acid and 15% HCl acid. The
use of formic acid as an extender did not give satisfactory
results.
TABLE I
__________________________________________________________________________
TEST INHIBITOR COUPON CORR. RATE NO. TYPE GPT TYPE ACID
(LB/FT.sup.2)
__________________________________________________________________________
1 -- -- CR-13 10% FORMIC 0.0442 2 A 5 CR-13 10% FORMIC 0.0083 3 B 5
CR-13 10% FORMIC 0.0082 4 C 5 CR-13 10% FORMIC 0.0097 5 D 5 CR-13
10% FORMIC 0.0089 6 -- -- CR-2205 10% FORMIC 0.0009 7 A 5 CR-2205
10% FORMIC 0.0006 8 B 5 CR-2205 10% FORMIC 0.0004 9 C 5 CR-2205 10%
FORMIC 0.0007 10 D 5 CR-2205 10% FORMIC 0.0008 11 -- -- N-80 10%
FORMIC 0.1684 12 A 5 N-80 10% FORMIC 0.0162 13 B 5 N-80 10% FORMIC
0.0149 14 C 5 N-80 10% FORMIC 0.0156 15 D 5 N-80 10% FORMIC 0.0147
16 -- -- CR-13 15% 0.1438 17 A 2 CR-13 15% 0.0048 18 A 5 CR-13 15%
0.0048 19 B 2 CR-13 15% 0.0111 20 B 5 CR-13 15% 0.0101 21 C 2 CR-13
15% 0.0066 22 C 5 CR-13 15% 0.0064 23 D 2 CR-13 15% 0.0124 24 D 5
CR-13 15% 0.0067 25 -- -- CR-2205 15% 0.1268 26 A 2 CR-2205 15%
0.0664 27 A 5 CR-2205 15% 0.0496 28 B 2 CR-2205 15% 0.1209 29 B 5
CR-2205 15% 0.1066 30 C 2 CR-2205 15% 0.0486 31 C 5 CR-2205 15%
0.0421 32 D 2 CR-2205 15% 0.1135 33 D 5 CR-2205 15% 0.0954 34 -- --
N-80 15% 0.0602 35 A 5 N-80 15% 0.0061 36 B 5 N-80 15% 0.0105 37 C
5 N-80 15% 0.0069 38 D 5 N-80 15% 0.0079
__________________________________________________________________________
TABLE II
__________________________________________________________________________
TEST INHIBITOR COUPON CORR. RATE NO. TYPE GPT TYPE ACID
(LB/FT.sup.2)
__________________________________________________________________________
1 -- -- CR-13 10% FORMIC 0.0952 2 A 5 CR-13 10% FORMIC 0.0182 3 B 5
CR-13 10% FORMIC 0.0210 4 C 5 CR-13 10% FORMIC 0.0224 5 D 5 CR-13
10% FORMIC 0.0227 6 -- -- N-80 10% FORMIC 0.3487 7 A 5 N-80 10%
FORMIC 0.0340 8 B 5 N-80 10% FORMIC 0.0335 9 C 5 N-80 10% FORMIC
0.0386 10 D 5 N-80 10% FORMIC 0.0309 11 -- -- CR-13 15% 0.3324 12 A
5 CR-13 15% 0.0177 13 B 5 CR-13 15% 0.0398 14 C 5 CR-13 15% 0.0217
15 D 5 CR-13 15% 0.0297 16 -- -- N-80 15% 0.1188 17 A 5 N-80 15%
0.0116 18 B 5 N-80 15% 0.0232 19 C 5 N-80 15% 0.0128 20 D 5 N-80
15% 0.0174 21 -- -- CR-13 12/3 MUD 0.6534 22 A 5 CR-13 12/3 MUD
0.0424 23 B 5 CR-13 12/3 MUD 0.0634 24 C 5 CR-13 12/3 MUD 0.0561 25
D 5 CR-13 12/3 MUD 0.0760 26 -- -- N-80 12/3 MUD 0.1244 27 A 5 N-80
12/3 MUD 0.0239 28 B 5 N-80 12/3 MUD 0.0313 29 C 5 N-80 12/3 MUD
0.0256 30 D 5 N-80 12/3 MUD 0.0304 31 -- -- CR-13 6/1.5 MUD 1.1556
32 A 5 CR-13 6/1.5 MUD 0.0171 33 B 5 CR-13 6/1.5 MUD 0.0249 34 C 5
CR-13 6/1.5 MUD 0.0189 35 D 5 CR-13 6/1.5 MUD 0.0258 36 -- -- N-80
6/1.5 MUD 0.1094 37 A 5 N-80 6/1.5 MUD 0.0112 38 B 5 N-80 6/1.5 MUD
0.0160 39 C 5 N-80 6/1.5 MUD 0.0122 40 D 5 N-80 6/1.5 MUD 0.0201
__________________________________________________________________________
TABLE III
__________________________________________________________________________
TEST INHIBITOR ADDITIVE COUPON CORR. RATE NO. TYPE GPT TYPE AMT.
TYPE ACID (LB/FT.sup.2)
__________________________________________________________________________
1 -- -- -- -- CR-13 10% FORMIC 0.2478 2 A 05 -- -- CR-13 10% FORMIC
0.0714 3 A 20 -- -- CR-13 10% FORMIC 0.0628 4 B 05 -- -- CR-13 10%
FORMIC 0.0856 5 C 05 -- -- CR-13 10% FORMIC 0.0801 6 C 20 -- --
CR-13 10% FORMIC 0.0730 7 -- -- -- -- N-80 10% FORMIC 0.4340 8 A 05
-- -- N-80 10% FORMIC 0.1691 9 A 20 -- -- N-80 10% FORMIC 0.1193 10
B 05 -- -- N-80 10% FORMIC 0.1813 11 C 05 -- -- N-80 10% FORMIC
0.1773 12 C 20 -- -- N-80 10% FORMIC 0.1317 13 -- -- -- -- CR-13
15% 0.8038 14 A 05 -- -- CR-13 15% 0.1578 15 A 10 -- -- CR-13 15%
0.2279 16 A 10 FORMIC 10 GPT CR-13 15% 0.2413 17 A 10 KI 10 PPT
CR-13 15% 0.0515 18 A 10 KI 20 PPT CR-13 15% 0.0489 19 A 10 KI 20
PPT CR-13 15% 0.0422 20 A 10 KI 30 PPT Cr-13 15% 0.0398 21 A 20 --
-- CR-13 15% 0.2862 22 A 20 FORMIC 10 GPT CR-13 15% 0.2363 23 A 20
KI 20 PPT CR-13 15% 0.0543 24 A 20 KI 30 PPT CR-13 15% 0.0451 25 A
30 -- -- CR-13 15% 0.2263 26 A 30 FORMIC 10 GPT CR-13 15% 0.2286 27
B 05 -- -- CR-13 15% 0.2978 28 B 10 KI 20 PPT CR-13 15% 0.0589 29 B
10 KI 30 PPT CR-13 15% 0.0298 30 B 20 KI 20 PPT CR-13 15% 0.0470 31
B 20 KI 30 PPT CR-13 15% 0.0420 32 C 05 -- -- CR-13 15% 0.1853 33 C
10 KI 20 PPT CR-13 15% 0.0560 34 C 10 KI 30 PPT CR-13 15% 0.0480 35
C 20 -- -- CR-13 15% 0.3621 36 C 20 KI 20 PPT CR-13 15% 0.0565 37 C
20 KI 30 PPT CR-13 15% 0.0503 38 -- -- -- -- N-80 15% 0.5016 39 A
05 -- -- N-80 15% 0.0692 40 A 10 -- -- N-80 15% 0.0743 41 A 10
FORMIC 10 GPT N-80 15% 0.0770 42 A 10 KI 10 PPT N-80 15% 0.0462 43
A 10 KI 20 PPT N-80 15% 0.0303 44 A 10 KI 20 PPT N-80 15% 0.0399 45
A 10 KI 20 PPT N-80 15% 0.0403 46 A 10 KI 30 PPT N-80 15% 0.0271 47
A 10 KI 30 PPT N-80 15% 0.0327 48 A 20 -- -- N-80 15% 0.0795 49 A
20 FORMIC 10 GPT N-80 15% 0.0729 50 A 30 -- -- N-80 15% 0.0663 51 A
30 FORMIC 10 GPT N-80 15% 0.0712 52 B 05 -- -- N-80 15% 0.1140 53 B
10 KI 20 PPT N-80 15% 0.0537 54 C 05 -- -- N-80 15% 0.0816 55 C 10
KI 20 PPT N-80 15% 0.0591 56 C 20 -- -- N-80 15% 0.1014 57 A 10 KI
20 PPT CR-13 12/3 MUD 0.0577 58 A 20 -- -- CR-13 12/3 MUD 0.2169 59
B 10 KI 20 PPT CR-13 12/3 MUD 0.0889 60 C 10 KI 20 PPT CR-13 12/3
MUD 0.0761 61 C 20 -- -- CR-13 12/3 MUD 0.2704 62 A 10 KI 20 PPT
N-80 12/3 MUD 0.0263 63 A 10 KI 20 PPT N-80 12/3 MUD 0.0308 64 A 10
KI 30 PPT N-80 12/3 MUD 0.0217 65 A 20 -- -- N-80 12/3 MUD 0.0631
66 B 10 KI 20 PPT N-80 12/3 MUD 0.0446 67 C 10 KI 20 PPT N-80 12/3
MUD 0.0391 68 C 20 -- -- N-80 12/3 MUD 0.0676 69 A 20 -- -- CR-13
6/1.5 MUD 0.0629 70 C 20 -- -- CR-13 6/1.5 MUD 0.0693 71 A 20 -- --
N-80 6/1.5 MUD 0.0231 72 C 20 -- -- N-80 6/1.5 MUD 0.0237
__________________________________________________________________________
TABLE IV
__________________________________________________________________________
TYPE INHIBITOR ADDITIVE COUPON CORR. RATE NO. TYPE GPT TYPE AMT.
TYPE ACID (LB/FT.sup.2)
__________________________________________________________________________
1 -- -- -- -- CR-13 12/3 MUD 0.8851 2 A 40 KI 80 PPT CR-13 12/3 MUD
0.0870 3 -- -- -- -- N-80 12/3 MUD 0.7153 4 A 20 FORMIC 20 GPT N-80
12/3 MUD 0.1833 5 A 40 KI 50 PPT N-80 12/3 MUD 0.0539 6 A 40 KI 80
PPT N-80 12/3 MUD 0.0420 7 C 40 KI 50 PPT N-80 12/3 MUD 0.0566 8 --
-- -- -- CR-13 15% 0.8403 9 A 40 KI 80 PPT CR-13 15% 0.0939 10 --
-- -- -- N-80 15% 0.7044 11 A 20 FORMIC 20 GPT N-80 15% 0.2309 12 A
40 KI 50 PPT N-80 15% 0.0798 13 A 40 KI 80 PPT N-80 15% 0.0615 14 C
40 KI 50 PPT N-80 15% 0.0754
__________________________________________________________________________
ECOTOXICITY
The toxicity of the compounds was measured by assessing the
concentration of each compound required to kill 50% of the
microorganism Tisbe battagliai. This concentration is termed the
LC50 and is expressed in mg/l. The samples used in the tests are
described below.
______________________________________ Sample 1 TOFA/TETA
IMIDAZOLINE +1 equivalent of acrylic acid (No Salt) (Same as
Inhibitor A with lower substitution) Sample 2 Same as 1 except 2
equivalents of acrylic acid (No Salt) (Same as Inhibitor A with
lower substitution) Sample 3 Same as 1 except 3 equivalents of
acrylic acid (No Salt) (Inhibitor A)
______________________________________
The results are given in TABLE V.
TABLE V ______________________________________ TIME CATEGORY OF
LC.sub.50 (mg/l) IDENTIFICATION (HRS) <10 10-100 100-1000
______________________________________ Sample 1 24 X 48 X Sample 2
24 X 48 X Sample 3 24 X 48 X
______________________________________
It can be seen from this that the addition of more acrylic acid
groups (i.e. increasing the N-substitution) gives lower
toxicity.
Additional ecotoxicity tests were carried out using the following
samples:
______________________________________ Sample 4 Duomeen T - acrylic
acid (1 eq.).sup.2 ampholyte (30%) Sample 5 Duomeen T - acrylic
acid (2 eq.).sup.2 ampholyte (30%) Sample 6 Duomeen T - acrylic
acid (e eq.) ampholyte (30%) (Inhibitor B)
______________________________________ .sup.2 Same as Inhibitor B
but with lower substitution.
The results are given in TABLE VI.
TABLE VI ______________________________________ SCREENING TEST FOR
THE TOXICITY OF CHEMICALS TO TISBE BATTAGLIAI SAMPLE TIME CATEGORY
OF LC50 (mg/l) IDENTIFICATION (HRS) <10 10-100 100-1000 <1000
______________________________________ Sample 4 24 X 48 X Sample 5
24 X 48 X Sample 6 24 X 48 X
______________________________________
Growth inhibition tests have also been carried out to assess the
impact of the compounds on the marine algae Skeletonema costatum.
This is a test which is becoming required by some off-shore
authorities, and is therefore of particular interest when
considering the practical applications of the compounds.
______________________________________ MARINE
PHYTOPLANKON-INHIBITION OF GROWTH RATE TEST CONDITIONS
______________________________________ Test Organisms: Skeletonema
Costatum (Greville) Cleve, Clone Skel-5. Incubation: 3 Days at
14.degree. C., in light/darkness cycles of 14 hrs./10 hrs. pH
Tolerance: 7.5-9.2. Test Samples: Aliquots of each sample are
weighed into phytoplankton medium and extracted; moderate shaking
for 20 hrs. at 14.degree. C. Control Compound: Na-dodecyl-sulphate.
Normally a concentration of 1.3 mg/kg gives 30 to 70% of normal
growth rate. Measured in this test: 30% to 55%.
______________________________________
RESULTS
Results are calculated as the concentration of compound required to
inhibit 50% growth of algae during three days of exposure, termed
EC.sub.50, given in mg/kg (ppm). the interval EC20 to EC80 is also
given. The results are presented in TABLE VII.
TABLE VII ______________________________________ INHIBITION OF
GROWTH RATE OF ALGAE SKELETONEMA COSTATUM SAMPLE EC.sub.20
EC.sub.50 EC.sub.80 ______________________________________ Sample 4
0.30 0.45 0.63 Sample 5 1.26 2.00 2.82 Sample 6 1.88 3.16 4.47
______________________________________
It can be seen from this that the compounds containing secondary
and tertiary amines are much less ecotoxic than those which contain
a significant proportion of primary amines.
* * * * *